Abstract

The project aimed to study the diffusion of specific counter anions into a conducting-polymer film by the choice of various counter-ions in the solution, cyclic voltammetry behaviour of the conducting polymers and investigation of the morphology of the polymer. It has been observed that the redox activity was strongly affected by counter anion type and size in the solution, and in the case of longer anions such as sodium dodecylbenzenesulfonate (NaDBS) the whole cyclic voltammetry (CV) curve was shifted in the cathodic direction. The shapes of CV curves for different counter anions have been analysed. In order to study the rate of ion diffusion into polymer films a series of experiments was done to determine the diffusion coefficient electrochemically. A current pulse was applied to polymer films for a short time and then they were given a period of time to return to equilibrium. The diffusion measurements of in electrochemically prepared poly (N-dodecylpyrrole) and polypyrrole films have been studied in electrochemical cells containing lithium perchlorate, tetramethylammonium chloride in acetonitrile and sodium dodecylbenzenesulfonate in water and the effects of the size of the diffusing ions on diffusion coefficients have been discussed. An increase in diffusion coefficients in the order of Cl[sup]- < ClO[sup]-[sub]4 < DBS[sup]-at 296.15 K has been observed. The electrosynthesis conditions (deposition potential) had a great effect on the morphology, as SEM studies revealed. Great ranges of morphology were obtained by using different counter anions.